The present invention is generally directed to leading arm and trailing arm vehicle suspension system types. More specifically, the present invention is directed to suspension systems having a longitudinally extending arm connecting a fabricated hollow vehicle axle to a vehicle frame hanger.
Leading and trailing arm vehicle suspension systems are known. Such suspensions typically have a longitudinally extending arm that is pivotally connected at a proximal end to a vehicle frame hanger and generally rigidly connected at a distal end to a vehicle axle, typically through an axle seat or other intermediate suspension component. The arm typically provides a bending stiffness to control axle windup and longitudinal stiffness to control axle position. As used herein, the term arm shall be construed to exhibit the characteristics expressed within this paragraph.
Leading arm vehicle suspension systems are those types of suspensions wherein the vehicle axle is positioned forward of the frame hanger. Trailing arm vehicle suspension systems are those types of suspensions wherein the vehicle axle is positioned rearward of the frame hanger.
Leading arm vehicle suspension systems are illustrated in this patent application, for purposes of providing a frame of reference with regard to the direction and for purposes of uniformity. However, those skilled in the art will understand that the principles of the present invention are applicable to trailing arm vehicle suspension systems, as well. Therefore, for each example, each description of a leading arm vehicle suspension system shall be considered to be a description of and shall also apply to a trailing arm vehicle suspension system exhibiting similar structural and functional characteristics.
While prior leading and trailing arm vehicle suspension systems have been adequate for certain purposes, they have lacked some of the advantages obtainable with the embodiments of the present invention. Many of these advantages are clearly described herein and others shall be readily apparent to those skilled in the art.
One advantage achieved by the present invention is the use of a leading or trailing arm in a leading or trailing aim suspension system wherein the arm assembly includes an axle bracket attached to a tubular vehicle axle by, for example a durable through-bolt connection, and having a vertical plane permitting attachment thereto of a suspension component such as a trailing arm or leading arm of the type used in trailing arm suspension systems and leading arm suspension systems, respectively.
Another advantage achieved by the present invention is the use of such an axle bracket having a transverse torque rod attachment included in the axle bracket casting.
Another advantage achieved by the present invention is the use of such an axle bracket having shock attachment locations included in the axle bracket casting.
Another advantage achieved by the present invention is the use of such an axle bracket having rack and pinion attachment locations included in the axle bracket casting.
Another advantage achieved by the present invention is the use of such an axle bracket having air spring attachment locations included in the axle bracket casting.
Another advantage achieved by the present invention is the use of such an axle bracket having caster wedge attachment locations included in the axle bracket casting and further having slotted caster adjustment holes and a rounded pivot hole to permit assembly without a fixture.
A still further advantage achieved by the present invention is the use of an arm assembly with an arm having a Z-shaped cross-section fastened to the axle bracket along its vertical plane and thereby providing an efficient load transfer from the arm to the axle bracket casting to avoid or substantially reduce the development of stress risers around the fasteners used for such fastening and to produce optimal stress distribution.
Another advantage achieved by the present invention is use of such a z-shaped arm having its shear center in line with the attachment of the arm to the axle bracket casting thereby avoiding twisting and associated torsion in the part.
Another advantage achieved by the present invention is use of such a z-shaped arm with top and bottom flanges efficiently tapered to optimize the section for weight and to enhance compliance so the arm is not overly stiff during suspension roll.
Another advantage achieved by the present invention is use of voided bushings with such a z-shaped arm to further control roll stiffness within a predetermined favorable range.
Another advantage achieved by the present invention is the use of such a z-shaped arm having a transverse torque rod bracket connected thereto.
Another advantage achieved by the present invention is the use of such a z-shaped arm having rack and pinion attachment locations included in the beam.
Another advantage achieved by the present invention is the use of such a z-shaped arm having a stamped configuration to achieve ease of manufacture and to accommodate packaging limitations.
Another advantage achieved by the present invention is use of such an arm assembly to reduce suspension system weight, part count, assembly time and assembly complexity.
Another advantage achieved by the present invention is the use of such an arm assembly to reduce failure modes and improve product integrity.
Another advantage achieved by the present invention is the ability to tune roll stiffness of the suspension by optimizing the compliance of the arm and the bushings used to connect the beam to its associated vehicle frame hanger.
These and other advantages of the preferred forms of the invention will become apparent from the following description. It will be understood, however, that an apparatus could still appropriate the invention claimed herein without exhibiting each and every one of these advantages, including those gleaned from the following description. The appended claims, not any advantages recited or implied herein, define the subject matter of this invention. Any and all advantages are derived from the preferred forms of the invention, not necessarily the invention in general.